How do you repair a cracked toilet tank?

There is no really good way to repair a cracked toilet tank. If your toilet is fairly new, you may be able to purchase the tank only, but most likely, it will be necessary to replace both pieces of your toilet. The good news is that dual-flush and comfort-height toilets are less expensive. It could be a good opportunity.

Toilets and tanks are cheap enough to buy that I would consider replacing one before repairing one. If the crack is not leaking, I would just leave it alone. Otherwise a simple crack can be filled with special sealant purchase at a hardware store but why bother? It will only start to leak again.

in my opinion, the only way would be to change it. But if you really want to repair it, then you should find a really good glue that can do the job. Of course, it depends on what the tank is made of. I've heard that epoxy glues, the ones with 2 parts are really good.